Calculating mechanism.



F. A. POOLE.

CALGULATING MBCHANISM.

APPLICATION FILED 00T.8,19o9.

Patented Mar. 18, 1913.

I 57 mmuunurg! Il Il FREDERICK A. POOLE, OF CHICAGO, ILLINOIS.

CALCULATING MECHANISM.

Specicationof Letters Patent.

Patented Mar. 18,1913.

Application tiled October 8, 1909. Serial No. 521,682.

To all whom fe' may concern:

Be it known that I, Fnnnnmon A. POOLE, a resident of Chicago, in thecounty of Cook and State o-f Illinois, have invented certain new anduseful Improvements in Calculating Mechanism, of which the.ft-)'llo'v'ving is a full, clear, and precise specification.

My invention relates to calculating mechanism which is particularlyadaptable for calculating and indicating directly the average rate ofmotion, although the mechanism is useful for performing othercalculations and indicating results thereof.

Average rate of motion combines sets of distance increments and timelincrements to produce rate `increments which are averaged to produce afinal average rate element. This calculation involves processes of d .iision. If two natural numbers are added'vve obtain a sum, and if thenumbers are subtracted We obtain a. difference. However, if .thelogarithms of the natural numbers are added the anti-logarithm of thesum Will be the product of the natural numbers, and if the logarithms ofthe-natural numbers are subtracted the antidogarithms of the differencewill be the quotient of the natural numbers. Likewise, in the case oftwo moving members, b v adding the distance traveled by the members Teobtain the sum of the distances and if the distances traveled by the,men'ibers are subtracted We obtain a difference of the distances, Whileif the logarithms of the distances traveled by the members are added theanti-logarithm ofthe sum will be the product of the distances, rithmsofthe distances traveled are sub? traoted the anti-logarithm of thedierence will be the quotient of the distances.

The main Object of my invention, therefore, is to provide mechanismcomprising two motion trains driven at one end in prol portionrespectively to the elements of the quotient, the arithmetic motionsbeing translated by the trains into logarithmic motions to produce alogarithmic difference, and to provide furtherindicating mechanism Whichoperates logarithmically to indicate the antilogarithm of thelogarithmic difference and thus to indicate the arithmetic quotient ofthe element. For example, if the arithmetic dividend element is distanceand the arithmetic divisor element is time, the indication Will be thearithmetic quotient. representing rate. If a number of elementincrements are entered on the motion trams the resulting and if theloga-` -9 having side flanges 10 and quotient increments will beaveraged up so thatl the final indication will represent the arithmeticaverage rate, and therefore, if a number of increments of time areentered on a time train and a number of distance increments entered on adistance train the indication will give the average of the various rateincrements and Will represent the average rate. .a

I shall describe an embodiment of my invention which is particularlyadaptable for indicating average rate of travel of vehicles suchautomobiles, and from this description `it vvill be plain that themechanism can be used directly or in modified form for in\ dicatingaverage rate of other elements, as,.

for example` the average rate of consumption of electric current or theaverage rate of air How or Water flow.

In the accompanying drawing which illustrates one embodiment` of myinvention which adapts it particularly for use on vehicles Figure 1 is afront view of an instrument for carrying out the purpose and features ofmy invention, parts of the inclos ing case being broken away, Fig. 2 isa sectional view taken on plane 2-2, Fig. 1, and Fig. 3 is a plan View,the top of the inclosing case being removed.

The inclosing case 1 for the instrument shown is rectangular in shapeand journals a shaft 2 in its front and rear Walls 3 and 4, as bestshown in Fig. 3. On this shaft'are pivoted the two differential members5' and G having respectively the internal teeth 7 and 8. Secured to theshaft 2 is a cylinder 11 between which are pivoted sets of differentialpinions. Each set comprises pinions 12 and 13 mounted on shafts 111 and15 respectively,

which shafts are journaled in the flanges 10 and 11. Pinions 12 and 13mesh With each other and the pinions 12 of the sets mesh with teeth 7,While the pinions 13 of the sets mesh With teeth 8. The outside of thedifferential members 5 and 6 present. cylindrical surfaces of equaldiameter. A shaft 16 journals in the top and bottom walls 17 and 17 ofthe casing 1 and carries a spool shaped cam 18 whose concave sides havesubstantially the same radius as that of the differential members 5 andG, the shaft 16 being situated so that the surface of the cam willcoincide? with the ysurface of the differential member G. Cut about thesurtace of the cam is a cam slot 19 receiving a Q intents tooth 20extending from differential memto the distance covered by the vehicle.The

shaft 21 parallel-With shaft 1,6 is journaled in the. top and bottomWalls 17 and 17 ot the casing, but. is at the other .side of thedifferential members and carries a vspool shaped cam 22 which is'similar tofcam 18l and v'which receives thesection of the sur'- face ofdifferential-member 5 diagonally op posite the surface covered by cam 18'on differential member 6. @am 22 has a. spiral groove 23 receivingatooth 24 extending-5 from differential member- 5 so that turning otthis cam Will result in rotation ot said member 5. ln practice shaft2lconnects with and is driven by time mechanism such as a cloclr 25.

-As rate is a .quotient cams 18 and 22 must be driven in oppositedirections. lt the cams are driven arithmetically diderent rates thediri'erence in movement ot the dit terential members would indicatemerely the arithmetical-diderence between the individual movements otthe gears. Therefore, 'in order that the differential movementvmay beindicative ot rate the differential members must be drivenlogarithmically. The cam grooves must, therefore, be in the form otlogarithmic spirals. ditlference in distances of travel ot the terentialmembers Will be equal tool" proportional to the anti-logarithm ot inequotient or rate elements, and in order to directly indicate thequotient the diiterence movement -which is communicated to the cylinder9 and shaft 2 is 'transmitted through suitable gears 26 and 2'( to apointer 28 ytraveling over a dial 29 on which the arithmetic rateindicating numbers are spaced logarithmically. The clock and thevehicle, therefore, produce arithmetic bodily rotation ot the gears' 22and i8 respectively in proportion to thetnne and distance elements, andthis arithmetic movement is translated into ,logarithmic movement ofthe' vc litterential members While the logarithmic difference ofmovement of the differential members is translated into arithmeticindication ont the rate element.

' Suppose that the driving connection betvveen cam 18 and thevehiclerunning gear is such that the cam will turn one revolution toreach mile ot travel, then, the capacity ot the instrument in miles ottravel `will be de termined by the number or turns in the spiral groove19. The mostconvenient l logarithmic base to use for devices of thiskind is ten and therefore cam 18 will have resent six minutes.

ten turns as shown, Vthe capacity in miles of travel then being tenmiles. Cam`22 also has ten turns and if this cam is driven tenrevolutions per hour each turn would rep- The time cam will rotate at aconstant speed, that is, at a rate of one revolution per six minutes.age rate of travel of the vehicle is ten miles per hour, then both camsrotate at the same speed and t-he pointer remains at rest. `If theaverage rate of speed becomes greatertbr less than ten miles per hourthe pointer Will Y move to give the proper indication. Ten miles and onehour are very small space and time capacities particularly for longdistance vvehicles such as automobiles Where a capacity of i000 milesfor distance and 100 hours for time Would be much more desirable. lt iseasily seen that ir these large distance and time capacities were to beaccommodated on av single nam the cams and thel diii'erential mechanismswould have to be exceedingly large. Instead, therefore, of havingsingle' cams l utilize a number of smaller cams geared together insuitable' ratio and associated With the differential members to causethe proper rotation thereof. As shown in Fig. l the distance element iscontrolled by a. train of three cams, 18, 29 and 30. These cams aresimilar and are of length so that each cam covers ninety degrees of thecircumference of the differential member 6. Cam 29 is mounted on a shaft3l which journals in the side Walls 32 and 33 of the casing, While cam30 is carried on shaft 34 journaled at its ends in the top and bottom'Walls 17 and 17. Shaft l0 carries a Worm 35 Which meshes with a Wheel 36carried by shaft 3l. Shaft 3l at its other end carries a Worm 37 meshingwith a Worm Wheel 38 on shaft 34:. The gear relations between the wormand Worm Wheels is sucl'ithat vcam 29 rotates one-tenth as fast as cam1S and cam .30 rotates one-tenth as fast as cam 29. The time element iscontrolled byua train of three cams, 22,39 and 40, cam 39 being mountedon shaft 4-1 and cam Al0 being mounted on shaft l2 Shaft 2i carries avWorm t3 meshing with Worm `Wheel on shaft 41, and shaft at its otherend carries a worm 45 meshing with Worm Wheel t6 on shaft fl-2, so thatcam 39 rotates one-tenth as tast as cam 22 and cam .ll-O rotatesone-tenth as tast as cam 39.

Cams 22, 39 and 40 each cover onegifourth of the circumference otdifferential member 5, the ends ot the cams engaging so that the camgrooves lthereof connect With each other.

It' Athe aver-v illith'this arrangement of cam mechanism a very compactconstruction is possible with a larve distance, time, and average ratecapacity. Each cam having ten turns, and the cams ot' each train beingprogressively geared from 10 to l, each train constitutes a `decimalprogression in which the gears repnoteer/e resent the decimal orders.- lWith cam l' alone the distance capacity would be only ten miles. Byadding cam 29 the distance.

' time capacity to ten hours and the addition vso ' cams of each traincan of cani increases the time capacity toene hundred hours. The caringbetween the esuch that the contact lines of the gears With theditierential members will be in a common plane, so that tooth 2() willserve for engagement with all the cams-ot the distance' train and sothat tooth 24 Will serve for engagement with all the cams ofthe timetrain. 'However7 with the worm and worm wheel gearing arrangementasshown cam 29 is slightly to one side of thev commonplane of the gears 18and 30, and likewise cam/39 of the time train is slightly to one side ofthe plane of gears 22 and 40. I therefore provide additional teeth 20and 24', tooth 20" being in position to be carried into the groove ofcam 29 when tooth 2O leaves the groove or cam 18 and likewise tooth 24being in position to he carried into the groove of cam 39 when tooth 24leaves the groove of cam 22. rleeth 20 and 24, however, cooperate withcams 30 and-40 respectively as soon as teeth 2G and 24 leave cams 29 and3,9 respectively.

If the spiral groove were laid oii' arithmeticallyeach turn would carrythrough a distance equal' to one-tenth ofthe cam surface, that is, foreach rotation of the cam the engaging tooth on the differential mem.-

ber would be moved an equal distance. ln

other Words, ifthe spiral were arithmetic the divisions along theengaging cam sun face .would be equal and would be along anajjithxnl'etical or natural scale 0 to 10, the first turn extending frompoints 0 to l,

the second turn from points 1 to 2, the third turn fromv points 2 to 3,and so on. it the ygroove'is a logarithmic spiral the distance l betweenturns are no longer equal but are in proportion to the logarithmicfunctions of on the arithmetic scale would, in the logthe naturalnumbers 0 to 10. For example, the first turn which extends from 0 to 1arithmic scale, extend from minus intinity 'to' 0, minus infinity and C*being respectively the logarithme of@ and 1. The second turni would endat oint 2 onthe arithmetic.- scale but on the ogarithrnic scale thesecond turn wonld lend at a; distance from .the logarithniic (l pointproportional to the number .301 which is the logarithm of 2. thesan-1eway the third turn would end at int 3 on the arithmetic scale haton the ogarithm'ic scale would end at a point pro- I portionfa'l to :47i which is the logarithm or" The first turn extending from minus ity toOvwould, of course, be endless and couldnot be utilized in anymechanical structure. ll, therefore, bring together or compress thefirst or 0 to l turn into a plane perpendicular to the cam axis at thebeginning of the second or 1 to 2 turn, so that the rst turns on thecams are zero turns which will cause no movement o the diderentialmembers 5 and 6. in other words, during the first mile andfirstsix *Iminutes of travel'the corresponding diden ential members will not be4driven. As Soon, however, as the second turns of the cams be'-comeetiective the diderential members will be driven andpro-perindication ofthe average rate given. v

fas the diierential cylinder 9' and the pointer geared thereto aredriven logarithmically in proportion to the logarithmic movementdierence between the differed tial members 5 and 6 the indicating pointson the dial must be spaced logarithmically so that the numbers at thesepoints can be construed arithmetically as indicative of the rateelement. lf thev distancel cam carries tooth '20 through the` zero turnin six minutes then both distance and time cams 18 and22 start at thesame time at their second turns or at an average rate equal to ten milesper hour, and the first point en the dial should, therefore, be ten. it'both the cams maintain uni-.torni rate of travel teeth 20 and 24 willreach the end of cams 18 and 22 at the saine time and the speed willstill oe ten miles per hour. it, however, cam. l@ rotated ten timesduring the firstievclution' of the cam 22, a distance of ten miles willhave been covered in six minutes and the average rate will. be onehundred miles per hour, and therefore thevlaid oil at logarithmicintervals around the circumterence of the dial. As has already beenmentioned, the cams each cover one itil@ itl@ fourth oli thecircumference of the'dfiflerential members, or in other'words, Veach camextends over a polar angle of ninety degrees. Therefore, when the tooth20 travels along the ent-ire length of cam 18 der ing the time thattooth 24 remains in the aero turn ot the time cam differential membei twill have rotated through ninety degrecs while member remained at rest,and the differential movement is ninety degrees. For 'this ninety degreeditlerence shaft 2 will rotate through only forty-tive degrees, andtherefore, in order that the pointer can move around three hundred sixtyde: grees to register "trom 10 to 10G the relation of gears 26 and 27must be 1 to 8. Betere starting a run of which the average speed is tobe determined the cam members are brought back to a starting position inwhich teeth Q0 and Q4: engage at the beginning of the Zero turns ot'cams 18 and 2Q. This re-setting can be accomplished in any desirablemanner. As shown, bevel pinions 17 and 18 are jourualed in walls 32 and38 controlled by actuating ends 49 and 50 at the outside of the casing.The pinions mesh with bevel teeth 5l and 52 cut in the edges of cams 18and 22 respectively. By turning the ends 49 and 50 the cams can berestored to bring the apparatus to starting position.

To illustrate more fully the operation of the mechanism, suppose thatthe parts are at their starting position, themachine is started and theclock simultaneously con neoted for operation so that cams 18 and 2:2will be rotated by the traveling vehicle and by the clock respectively.During the first mile of distance and the first six minutes of travelcams 18 and 22 respectively will not cause any movement of differentialmembers 6 and 5 respectively and the pointer will remain at rest at the10 mark. If at the end of the first six minutes the vehicle has traveledone mile then the second turns of the cams will become effectivesimultaneously and if the .vehicle continues to run at an average rateof ten miles per hour or one mile for every turn of the space cam thepointer would remain at rest at the 10 mark. As soon as the second turnsbecome effective the instrument will begin to register accurately as thedifferential member teeth travel along true logarithmic spirals. If thespeed of rotation of cam 18 is greater than the uniform speed ofrotation of time cam 22, then differential member 6 travels faster thandifferential member 5 and the pointer moves from the 10 toward the 20'-mark, and if the speed of rotation of cam 18 is less than that of' cam22 then the pointer will travel in the opposite direction, thepointer inany position indicating the average speed in miles per hour from thetime of starting the vehicle up to the time when the indication of thepointer is read. Suppose that the ten mile rate is kept up for the firsttwo miles or until the first two turns of both cams have been covered,and suppose that the operator then desires to increase his average speedto twenty miles per hour. The speed must then be increased beyond atwenty mile per hour rate until the average speed for the various milescovered will equal twenty.- For example. the operator can immediately,at the end ot the second turn, increase the speed to forty miles perhour and-he must keep up this speed for six minutes or one complete turnof the time cam. In other words, for the next turn of the time cam thedistance cam must rotate four turns to cover four miles in six minutes.This means that at the end ofthe sixth turn on the distanee cam and attheend ot' the third turn on the time eam the ditl'erential member t3will have traveled iour times the distance (logarithmic) that the timedifferential member 5 has traveled, and the differential shaft 2 willhave traveled only one-half the dilierential distance (logarithmic) ofthe cam members, and the pointer consequently will have moved from 10 tothe 20 mark to indicate an average speed of twenty miles per hour. Thedistance cam will have turned six revolutions, which is equivalent tosix miles of travel of the vehicle, and the time cam will have turnedonly three revolutions, which corresponds to a time period of eighteenminutes. Six miles have, therefore, been traveled in eighteen minutes,which is equivalent to an average rate of twenty miles per hour. Inother words. during the first six minutes of travel one mile wascovered; during the second six minutes another mile was covered; andduring the third six minutes four miles were covered, making a total ofsix miles for eighteen minutes, which is at an average rate of one milein three minutes or twenty miles per hour. In logarithmic figures thevarious dimensions would be as follows: Suppose that the circumferenceof the differential members is eight inches and that the engagingsurfaceof each cam is two inches. Iii' the first arithmetic turn 0 to 1 werelaid out logarithmically on the cam it would extend from minus infinityto 0, that is, it would extend in proportion to thelegarithms of 0 andAs already stated, it 4 wtmldbe mechanically impracticable to make useof this part of the curve, and this first section of the curve is,therefore, all accumulated into a zero turn which will cause no movementof the differential members. 4The part of the logarithmic cam which ispracticallyutilized extends arithmetically from 1 to 10 andlogarithmically from 0 to 1. If the cam were divided arithmetically wewould have nine equal divisions marked ofi by tenv equally distantspaced points running from 1 to' 10. The distances between turns,however, are logarithmic. The first logarithmic space from minusinfinity to 0 we have merged into a Zero turn. The logarithmic lrngth ofthe second space will be the difference between the logarithme of 1 and2 or .301, that is, the fraction which this length is of the entirelogarithmic distance from 0 to 1 is expressed by the decimal .301. Thethird logarithmic turn will have an active length equal to thedifference between t-he logarithms of 2 and 3 and will be represented by.17 6, and so on, the various decimals representing the nine logarithmicdistances and when added together equaling 1. The cam active surfaces,however, are two inches noname long and, therefore, to give the actualdistance in inches the various decimals must be multiplied by ,2. Forexample, the active distance of the second turn would be .602 inches,that is, the differential tooth upon passin through the second turn ofthe cam .slot will travel .602 inches; upon engagevment with the thirdturn it will move .352

inches?, and so.on,'the total distance traveled by a tooth uponengagement with one cam bein two inches. Therefore, with the examp e ofoperationv before given both teeth and 24 at the.ends of the secondturns will have traveled v`602A inches, there having been no movement ofthe teeth when engaged by the first or zero turn. Both cams traveled atthe same rate, the'v distance cam having traveled a distancecorresponding to two miles travel of the vehicle, Aand the time camhaving rotated for a periodof twelve. minutes. The speed was nowincreased to forty miles per hour and, therefore, for the next turn ofthe time cam the distance cam made four revolutions, tooth 24 being thenatvthe end of the third turn of the time cam, and tooth 20 beingat theend of the sixthturn of the distance cam. The entire distance traveledby tooth 24 from the't-ime of starting is now .477X2 inches 'or .954inches, and the entire distance traveled by tooth 20 from the time ofstarting is now .778X2 inches or liit inches. The logarithmic dierentialmovement is .301X2 inches or, .602 inches. The anti-logarithm of .301 is2 and, therefore, the pointer will travel to the second division on thescale and will indicate 20 to show that the aver- A age rate of speedhas reached twenty miles.

per hour. In other words, the rate multiple has become 2 and the averageSpeed has be 'come twice ten miles per hour vor twenty -miles per hour.During the time that the third, fourth, fifth and sixth turns of thedistance cam were associated with tooth 20 and turn three of the timecam was asso-.

ciated with'tooth 24 the ratemultiple varied vgradually from Al to 2,andthe pointer moved gradually from the 1'O`mark tothe 20 mark toindicate -all intervening average rate distances. If the rate of fortymiles per hour is maintained after the sixth turn 4 I and for the nextperiod of six minutes, tooth -20l will reach the end of the space camgroove and tooth 24.- will vreach the end of the fourth time turn.ATooth 20 will then have traveled'the entire length of cam 18 and tooth24 will have traveled a decimal part ofthe time cam represented by..602. The entire distance of cam 18 is represented by 1, .which isthelogarithm of 10, .and .602 is thelogarithm of 4. Therefore, the

- average rate* multiple .fis 2%, which means that the average rate isnow vtwenty-five miles .per hour and this will be indicated on scale.The pcinte'rfhas thus far traveled l lfrom 10 and has indicated all theintervening average rates between 10 and 25. Suppose that after theA endof the second turn, when'the speed. was ten miles per hour, it wasdesired. to -travel at a slower average speed, said eight miles perhour.Thespeed could then be reduced immediately to four miles per hour, sothat during the third turn o the time-cam tooth` 20 would travel overx@of the. third turn of the distance cam and the vaverage rate indicationwould then be eight miles per hour. If the four mile rate 1s maintainedduring the fourth turn of the time cam, tooth 20 will travel. over thenext 1% of the third turn of the distance cam, andthe average speed willthen becomeseven miles per hour. If the speed is now reduced to twomiles -per hour during the fifth turn of thetime cam, tooth. 20' willmove to the end of the third turn of the distance cam and the averagespeed will then be six miles per hour. Therefore,

at theend of the fifth turn of the time camv the vehicle will havetraveled three miles in thirty minutes 'or atan average rate'of sixmiles per hour, although the speeds for the` -V first and.` second turnswere ten' miles .per hour; forthe third and fourth turns four. miles perhour and for the fifth turn 'two miles per hour. Average rates below tenmiles per 'hour and above one lhundred miles per hour can readily beread on the dial. For example, for nine miles per hour the pointerwill'be at lthe 90 division, Vfor eight miles per hour at the 80division, and so on. If the dial has movedthrough the 10 mark and to the20 mark the indication will be two vhundred miles per hour, and

so on. The average speed most likely to be maintained'during ordinaryoperation of automobiles would be between ten and perhaps forty. milesper hour and the corresponding divisions on the dial being far-,thestapart for these averages, very accurate readings can lie-taken.'The dial, howp ever, can be made suiiiciently large so that allindications throughout the entire range could be accurately read tosmalldecimals.

Where each motion'train comprises -three ordergears', as shown, thegears'would have tobe re-set to the starting point after the vehiclehad' run one thousand miles or for one. hundred hours. v

In the arrangement .described the time' cam'rotates one `revolution eachsix minutes andthe distance cam`makesone revolution A for each mile -oftravel. The gearing rela@ tions-between (the clock and time cam and Ibetweenl the-vehicle and the distance cam can,.however,be varied toincrease or de# crease they capacityof the device. For ex ample, the'time cam could be rotated one; revolution -each thirty-six seconds andthe distance cam given a proportional -rate of.'Y rotation equal-tonnerotation foreach; tent-h y lution torl every ten miles of travel.

tions and. cam 22 two revolutions.

mile of travel.' The zero turn would then mile, but the capacity of thedevice would be reducedone-tenth and would be one hundred miles fordistance and ten hours for time. Likewise, the time cam can be given onerotation per hour and the distance -cam correspondingly driven to rotateone relvlclie zero turns would then cover respectively one hour and tenmiles, but the capacity of the device would be increased tenfold, andwould be ten thousand' miles for'distance and one thousand hours fortime. The gear ratio between the differential shat and the dial pointercould also be varied. If this gear relation were 1 to4 instead of 1 to 8the-pointer would travel through one hundred eighty degrees to' coverindications from 10 to 100. The gears and differential .mechanism neednot necessarily be of the shape shown but couldvhave other forms.Likewise, it is not necessary to use a logarithmic system whose base is10 vbut other logarithmic systems could be' employed, as

for example, the Napierian system could be' used which has a base4dii'erent from 10.- Y

rhe device couldV also be used for performing other calculations besidesaverage rate calculations. For example, division could readily beperformed with the device shown in the drawing. The dividend would beentered oncam 18 and the divisor on cam 22 and the dial would indicatethe quotient. For example, suppose the problem 1s to divide8 by 2. Cam18 is given eight revlie logarithmic, differential movement will betranslated into the arithmetic quotient which will'be indicated on thedial. If the numbers to be divided had several decimal orders then thedecimal `orders could be directly carried into the corresponding decimalorder cams. For example, the .units order of the dividend would beentered on units distance cam 18, the tens order of the dividend lwouldbe entered directly on tens distance cam 29,

v and so on, and the various orders of the divisorentered directly onthe corres ondipg order cams of the time train, the di erentlalmechanism associating the various entries and causing indication of thequotient on the dial. VFor example, if 125 is to be di-4 vided by 25 cam18 is given five revolutions, cam 29 two revolutions and cam 30 onerevolution, while cam 22 is given five ,revolutions and cam 39 tworevolutions, and the pointer will be moved to' indicate 5,-.which 1s thequotient of the two numbers,

The device is'not limited to calculating and indicating average rates ofspeed,but can be employed for determining average rates of other forceswhich can be translated into motion. For example, the device could beutilized to measure average electric power or watt consumption in anelectrical circuit. In this case the cam 18 would be connected with themovable element of the wattmeter, and cam 22 would be connected with atime member and the indications on the dial would then be representativeof average electric power consumption for a certain length of time. Inthe .same manner average current flow, water flow, air flow,

etc., can be measured.

- I do not, therefore, wish to be limited to the exact'construction,arrangement and use of 'the device which I have shown and described, andI desire to secure the following claims by Letters Patent;

1. In an average rate instrument, the combination of a member adapted tobe driven in proportion to distance, a second member adapted to bedriven in proportion to time,

vmeans associated with said members for continuously combining themovements thereof into movement proportional to average rate, 'and meansfor indicating at any instant the average rate.

2. In an average rate instrument, the combination of coperatingmechanism adapted to be 'driven in accordance with distance 'movementsof said driving members are translated into logarithmic movements of thereceiving members, an indicating member connected with the differentialmember to be actuated in proportion to the logarithmic differentialmovement between the receiving members, and a logarithmic scaleassociated with said indicating member to indicate the anti-logarithmicfunctions of the logarithmic differential movements.

mechanism, the combi-` Velements'ancl time elements and adapted to i 4.In calculating mechanism, the combif nation of differential mechanismcomprising two receiving members and a diiferential member associatedtherewith to be driven in accordance with the diierential movements .ofthe receiving members, a driving cam for each receiving member adapted:for connectio-n ,withl a driving force to be arithmetically driven'thereby, a cam tooth for each receiving member, each drivingvcam havingla logarithmic cam slot for receiving the tooth of `the correspondingreceiving member, the logarithmic cam slots and teeth coperating totranslate the arithmetic movements of the cams into logarithmicmovements of the receiving members, an indicating member driven by thedifferential member .in accordance with the logarithmic differentialmovement of the receiving members, and a logarithmic scale coperatingwith said indicating member to translate the logarithmic movements ofthe indicating member into arithmetic functions of such movements.

5. In a calculating instrument, the combination of differentialmechanism comprising two receiving members and a differential memberassociated therewith to be driven in accordance with the differentialmovement of said receiving members, a driving train for each receivingmember adapted for connection with driving forces to bedrivenarithmetically thereby, a cam tooth for each receiving member, eachdriving train comprising a plurality of decimal order cams connectedtogether in driving relation and each cam having a logarithmic cam slot,the logarithmic cam slots cooperating with the teeth on the receivingmembers to translate arithmetic movement of the train into logarithmicmovement of the receiving members, and meansl for indicating themovement of the dierential member.

6. In a calculating instrument, the combinat-ion of differentialmechanism comprising tion with driving forces to be driven arithtworeceiving members and a differential member associated therewith to bedriven in accordance with the differential movement of said receivingmembers, a driving train for each receiving member adapted forconnecmetically thereby, a cam tooth-for each receiving member,

. ing a' plurality of decimal order cams conynected together in drivingrelation and each cam having a logarithmic cam slot, the logarithmic/camslot-s.coperating with the teeth on the receiving members to translatearithmeticy movement of the train into logarithmic movement of thereceiving members, an indicating member drivenby the difierent-ialmember of the differential mechanism in accordance with the logarithmicdiderential movement of the receiving members,

' anda logarithmic scale coperating with the indicating member totranslate the logarithmic differential movement into arithmeticindication of such movement.

7. In yan average rate instrument, the combination of a member adaptedto be driven in proportion to distance, a second member adapted to bedriven in proportion to time, means associated with said members forcombining the movements thereof into movement proportional to averagerate, and means for indicating at any instant the average rate from thetime of starting of the distance member, said members and each drivingtrain compris'- means all operating continuously and simultaneously.

8. In an average rate indicating instrument, the combination of a memberadapted to be driven continuously in accordance with distance, anothermember adapted to be simultaneously driven continuousl in accordancewith lapse ofl time, means or continuously combining the movements ofthe members into movement indicative of average rate, and means for atany'instant indicating the average rate.

9. In a calculating machine, means adapted to be actuated in accordancewith increments of distance, means adapted to be actuated in accordancewith increments of time, integrating mechanism for automaticallyintegrating t-he increments in accordance with the resultant averagerate element, and indicating means operating simultaneously" during suchintegration to indicate at any instant the average rate element.

10. In a calculating device, the combination of a differential member, adriving member adapted to be moved arithmetically at a uniform fixedspeed and coupled with said .differential member to translate suchlarithmetic movement int/o uniformly accelerating movement of thedifferential member, a companion differential member, a second drivingmember adapted to be given increments of arithmetic movement at uniformspeed and to translate such increments of arithmetic movement intoaccelerating or retarding movement of the companion differential member,and differential mechanism associated with both differentialmeinmechanism to be driven to indicate the resultant of the relativemovements of the diderential members.

11. In an average rate calculating instrument, the combination of a timeelement adapted to be driven in accordance with lapse of time, adistance element adapted to be driven in accordance withdistance,differential mechanism comprising two .receiving members and adifferential member 'associated therewith to be driven inl accordancewith the differential movements of the receiving members, a logarithmiccam connecting said time element with one of said receiving members, anda logarithmic cam connecting said distance element with the other ofsaid receiving members Whereby 4said receiving members will belogarithmically driven and said 'differential member driveniin-accordance with the diferential movements of said receiving members,and indicating mechanism connected with'said differential member to bedriven thereby to indicate at any instant the average rate.

12. In an average rate calculating instru- -bers to be driven inaccordance with the differential .movement of said differentialv ment,the combination of a time element adapted to be connected with a sourceto be driven in accordance with la se of time, a distance elementadapted or connection with a source to -be driven in accordance withdistance, differential mechanism comprising two receiving members and adiiferential member connected therewith tol be driven in accordance withthe differential movement of said receiving members, logarithmicrdriveconnection between said time element and one of said receiving membersand logarithmic drive connection between said distance element and theother receiving member whereby said receiving members will be drivenlogarithmically, and indicating mechanism connected with saiddifferential member to be driven thereby in accordance with'thedifferential movement of said receiving members to indicate at anyinstant the average rate of movement of said distance element.

13. In a mechanical movement, in combination, two rotative elements,driving means imparting to each element an angular movement proportionalto the logarithm of the expressed value of the movement of said drlvingmeans, and a third element copcrating with said rotating elements,whereby its movement represents the sum or difference of saidlogarithms.-

14, In combination, a differential gear, a logarithmic cam 'adapted to'drive one side of said diii'erential gear, a vsecond logarithmic camadapted to drive'the opposite side o f said differential gear in reversedirection and a pointer connected to the middle member of said gear,whereby said pointer indicates the diierence between the oppositerotations of said opposite sides.

In Witness hereof, I hereunto subscribe my name this sixth day ofOctober A. D. 1909.

FREDERICK A. POOLE.

IVitnessesz,v

CHARLES J. SCHMIDT, NELLIE B. DEARBORN.

